How do you know if you’re overtraining?

What is overtraining?

Sore muscles, constant fatigue, and loss of motivation are common symptoms of overtraining, but did you know that your blood can also indicate if you need to take a few extra rest days? 

How does my blood indicate overtraining?

From your blood test, we can measure Testosterone:Cortisol (T/C) ratios, which are key to answering the question of whether or not you are overtraining.

But what exactly do T/C ratios measure?

T/C ratios measure both testosterone and cortisol levels. Testosterone is an anabolic hormone, meaning that it works to build muscle [1]. In contrast, cortisol is a catabolic hormone that works to break down muscle [2]. 

What does my number tell me?

By calculating the ratio of these two values, we can assess whether your body is in a muscle-building state or not. A larger T/C ratio indicates that your body has higher testosterone levels than cortisol, therefore your body is ready to build muscle. A smaller T/C ratio indicates that your body has higher cortisol levels than testosterone, therefore your body needs to rest and recover before it can efficiently develop muscle. 

So, how can I improve my T/C ratio? 

To increase your T/C ratio, you can:

  1. Increase your testosterone levels
  2. Decrease your cortisol levels

To increase testosterone levels, avoid taking supplements that claim to increase testosterone unless prescribed by your doctor. In fact, testosterone supplements are considered banned substances by WADA and USADA. Instead, try to implement a balanced diet full of Vitamin D and zinc. Both micronutrients are necessary precursors to the production of testosterone and can thereby help you increase your testosterone levels in a healthy manner [3] [4]. Foods that are rich in Vitamin D and zinc include beef, tuna, and crab.

To decrease cortisol levels, work on lowering your chronic stress levels [2]. This can be achieved by getting better, consistent sleep every night, or finding ways to healthily de-stress like yoga or meditation.

How can I find out what my T/C ratio is?

Get blood tested! To get your blood tested to find your T/C ratio, we have partnered with InsideTracker to provide our audience 25% off any and all testing done through InsideTracker when you book via the link below and use the code “NUTRITONALREV”.⁠


  1. Tyagi V, Scordo M, Yoon RS, Liporace FA, Greene LW. Revisiting the role of testosterone: Are we missing something?. Rev Urol. 2017;19(1):16-24. doi:10.3909/riu0716
  2. Lee DY, Kim E, Choi MH. Technical and clinical aspects of cortisol as a biochemical marker of chronic stress. BMB Rep. 2015;48(4):209-216. doi:10.5483/bmbrep.2015.48.4.275
  3. Wehr E, Pilz S, Boehm BO, März W, Obermayer-Pietsch B. Association of vitamin D status with serum androgen levels in men. Clin Endocrinol (Oxf). 2010;73(2):243-248. doi:10.1111/j.1365-2265.2009.03777.x
  4. Prasad AS, Mantzoros CS, Beck FW, Hess JW, Brewer GJ. Zinc status and serum testosterone levels of healthy adults. Nutrition. 1996;12(5):344-348. doi:10.1016/s0899-9007(96)80058-x
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